Differential rudder lever control



Aug. 27, 1946. P, HOL 2,406,374

DIFFERENTIAL RUD DER LEVER CONTROL I Filed Feb. 13, 1943 INVENTORPatented Aug. 27, 1946 UNITED STATE Pliny G. Holt, United States Navy v1 7 Application February 13, 1943, ScrialNo. 475,759

' Claims. (01. 244- 75) g '(Granted under the act of March 3, 1883, as

The invention relates to improvements in automatic pilots and moreparticularly to improved auxiliary control mechanism for use withautomatic pilots of the general character shown and described in myco-pending U. S. patent applica-' tion Serial No. 442,728, filed May 12,1942. I

An important object of the present invention is to provide an automaticgyro-pilot having aux iliary rudder control mechanism.

Another object of the invention is to provide an automatic gyro-pilotfor bomber aircraft having auxiliary rudder control mechanism operablein response to changes in the direction setting of a bombsight. 7

Yet another object is the provision of an auto matic gyro-pilot withrudder control mechanism including follow-up means transmitting motionin varying ratios depending on the rudder displacement.

A further object is to provide an automatic gyro-pilot having ruddercontrol mechanism in cluding a resilient follow-up connection.

The invention also aims to. provide an auto matic gyro-pilot for bombersincluding auxiliary rudder control mechanism of the character describedand provided with manually operable ad justing means.

The invention further aims to provide an aux iliary control unit whichmay be used in lieu of the auxiliary control unit shown and described inmy co-pending U. S. patent application Serial No. 466,301 filed November20, 1942.

Other objects and advantages of the invention will become apparentduring the course of the following detailed description, taken inconnection with the accompanying drawing, forming a part of thisspecification, and in which drawing,

Figure 1 is a diagrammatic perspective view of a gyro-pilot providedwith the auxiliary rudder control mechanism and showing the servo cableconnections to the aircraft control surfaces.

Fig. 2 is a fragmentary perspective view of the auxiliary control unit.

Figure 3 is a vertical transverse sectional view of the auxiliarycontrol unit substantially on the line 3-3 of Figure 2.

Figure 4 is an enlarged fragmentary sectional detail view taken on theline 4-4-4 of Figure 3.

Figure 5 is an enlarged view of the slotted connection between 11 and 81as viewed in Figure 3.

In the drawing, which for the purpose of illustration shows only apreferred embodiment of the invention, and wherein similar referencecharacters denote corresponding parts throughout the several views, theletter A generally desamended April 30, 1928; 370 0.-G. 757) ignates aconventional gyro-pilot provided with a bank and climb proportioningunit Band' an auxiliary rudder control unit 0.

In the example shown, the 'gyro-pilot A is of the general :ch'aractershown' and described in' U. S. Patent No; 1,992,970. granted to Sperry,JrQ, et al., and includes .a rudder servo control unit 20 having aconventional oil valve 2| for con-' trolling'tihe flow of oil throughpressure and exhaust conduits 2|a, 2| b, to the rudder servomotor 22,and an aileron and elevator-servo control unit 23 hydraulicallyconnected, as by" suitable conduits 24, 25 to the ailerons'ervo-motor 26and .elevator servo-motor 21, respectively. The rudder, aileron andelevator servo-motors 22, 26,21 are connected, as by suitable cables 28,29, 30 to the rudder, aileron and elevator surfaces 3|, 32, 33,respectively. These servo-motors may be' provided with a common shaft 34rotatable, as by a hand lever 35, to a position wherein the servo-motorsare by-passed for manual control.

' Attached to the servo control units 20, 23 is a bank and climbproportioning unit B,su'ch shown' and described in'myco-pending U. S.patent application, Serial No. 442,728, filed May 12, 1942. Thisbank andclimb proportioning unit B includes rudder, aileron and elevator followup" pulleys 36, 31, 38, provided with follow-up connections 39 40, 4|,respectively, attached to the rudder, aileron and elevator servo-motors22, 26,21. The unit B transmits motion fromthe rudder follow-upconnection 39 to the aileron and elevator followmp connections 40, 4|whereby the amount" of bank and climb is correlated to the amount ofrudder displacement of theaircraft.

The auxiliary rudder'servo control unit C includes an oil valve 42 forcontrolling the flow of oil throughpressure and exhaust. conduit's flz i42b, to the rudder servo-motor 22. In order to selectively control therudder servo-motor 22, a, valve 43 is interposed between the oil valves2|, 42 and the servo-motor 22. This selector valve 43 is connected tothe rudder servo-motor 22 by a pair of conduits 44 and to the oil valves2|, 42 by pairs of conduits 45,46. The valvej43 is provided with arecip-rocable piston 41 urged, as by an expansible coil spring 48, intoa position wherein the conduits 46 communicate with the conduits 44.Engaging the piston 41 is a rotary cam 49 turnable to shift the pistonsoasfto bring the conduits 45 into communication with the conduits;

Referring now to the auxiliary rudder control conventional intermeshingdifferential gears I64, I65, one gear I64 meshing with a spur gear I66fixed on the shaft 96 and the other gear plate 53 to which the oil valve42 is secured. Ex-

tending through the end plate 53 is a stem 54 forming part of the oilvalve 42 and supported, The

tral position will permit oil to flow through the I valve in adirectiondepending on the direction of shifting, of the stem. That portion of thestem 54 intermediate the lugs 55v is provided with a 1 I block-likesection 56 having an elongate'slot 51 extending longitudinally of .thestem and-defined l by spaced parallel side walls58, 5.9. Slidablyextending through the slot 51 is a lever 66 provided extendinglongitudinally of the side wall 59.

1 Thus the lever 66 is supported for sliding and swinging movementrelative to the block-likesection 56 .of the stem. Fixed to a laterallyoffset lug 63 forming an integral part of the lever '66 is the bightportion 64 of an inverted U-shaped leaf spring 65 having its parallelend portions 66 disposed in straddling relation tothe pin 6| and to apin 61 fixed in the side wall 59 of the blocklike section 56. The spring65 and pin 61 con- I stitute a resilient connection between the lever'15 with a lateral pin 6| passing through a slot 62 4 of the shafts 96and I62 will be transmitted to the sleeve 96.

In the operation of the auxiliary rudder control mechanism C, a changein the direction setting of the bombsight 1I will cause the arm 16 toswing whereby the lever 66, in rocking about the pin 88, will, throughthe resilient spring 65, shift the stem 54 of the oil valve 42 in adirection depending on the direction of change in the bombsight setting.Thus, when the piston 41 of the -valve.43 is positioned so as to bringthe oil valve :42 into'communication with the rudder servo-motor22, thisservo-motor will tend to deflect the rudder 3| so that the direction ofthe tor 22 will be transmitted through the cable 98 and pulley to theshaft 96 which will, through the differential gearing I64-|61, turn thesleeve 98'and crank 9|. The crank .pin 93 working in the slot 95 willswing thelever 81 in decreasing 66 andstem 54; Pivoted at one end of thelever l 66 is a rectangular button 68 disposed between spaced fingers 69of a forked arm '16. This arm I 16 may be associated with a bombsight IIwhereby one end of the arm 16 is swung in response to changes in thedirection setting of the bombsight. Follow-up means '15 is provided toswing the 3 other end of the arm 66 in response to changes in positionof the'rudder 3|. Extending through a vertical slot 16 in the side plate5| is a supporting stud 11 provided with an annular shoulstud 11 isprovidedwith. a reduced'free endportion '86'on whichis secured, as by awasher 8| 1 and cotter pin 82, a rotatable sleeve 83 provided at oneendwith an annular'shoulder 84. Ad-

justably supported on the sleeve 83 at slot 85, as

by a clamp nut 86,'is a lever 81 rigidly carrying a pin 88 that extends,at its free end, between spaced fingers forming a fork 89 at the end ofj the lever 66 opposite the button 68. When the 1 position of the stud11 is changed relative to the slot 85, its position is also changedrelative to the 1 slot 16 in the side plate 5| so that the lever 81 willremain in the same location.

Rotatably supported in the side plate 5| sleeve 96 fixedly carrying acrank arm 9| provided with a longitudinal slot 92 in which a crank pin93 is adjustably secured, as by a nut 94. This crank pin 93 at its freeend extends into a slot 95 in the end portion ofthe lever 81 oppositethe pin 88. Rotatable in the sleeve 96 is a follow-up shaft 96 on whichis fastened a conventional follow-up pulley 91 provided with a follow-upcable I 98 connected to the rudder servo-motor at fittin 99. Rotatableonthe shaft 96 is a worm wheel I66 meshing with a worm I6I fastened on ashaft 1 I02 that is manually rotatable as by turning a isa.

knob I63. This worm wheel I66 carries a pair of pinion I65 meshing witha spur gear I61 fixed on the sleeve 96." Thus, differential motiontransmittin means is provided wherebyrotation or either. one

ratios as the crank 9| departs in either direction from its neutralposition. Swinging of the lever 81 will, through the pin 88, shift thelever 66 so as to return the stem.54,to its original position. Thus, theoil valve 42 is recentered and further movement of the rudderservo-motor 22 away from neutral is prevented. As theaircraft turnstoward the direction of travel in order to satisfy the bombsight 1|, thearm-16 thereof will come mence retracting the lever 66 to its originalposition, and the rudder servo-motoris moved toward its neutralposition.

Various changes may be madein the form of invention herein shown anddescribed without departing from the spirit of the invention or thescope of the following claims.

The invention described herein may b manufactured and/or used by or forthe Government of the United States of America for govern stem, a leverextending through said slot and connected to said block for sliding andswinging movement relative thereto, resilient means associated with theconnection aforesaid for restraining said movement, means connecting oneend of said lever to said bombsight for shifting said lever at one end,and a follow-up connection responsive to changes in position of therudder. operating means for shifting the lever at its opposite end.

2. In an aircraft automatic pilothaving aileron operating-means,gyroscopic means and rudder operating means interconnected for automaticcontrol, the combination therewith'comprising; a bombsight and auxiliaryrudder control mechanism, said. auxiliary rudder controlmechanismcomprising a chassis, a stem mounted for slidable movement in saidchassis constructed and arranged to effect operation of the rudderoperating means, a block having, a slot carried by said stem, a leverextending through saidslot. and

connected to said block for sliding and swinging:

movement relative thereto, resilient means associated with theconnection aforesaid for restraining said movement, means connecting oneend of said lever to said bombsight for shifting said lever at one end,a follow-up connection responsive to changes in position of the rudderoperating means for shifting the lever at its opposite end, saidfollow-up connection including rotatable means carried by said chassis.

3. In an auxiliary rudder control, a rudder operating means including afluid motor, a motive fluid control valve for controlling the rudderoperating motor having a horizontal axially slidable operating shaft, alongitudinal horizontally opening slot in said shaft and a pinhorizontally extending from said shaft adjacent said slot, a'

vertically disposed lever having a pin for a fulcrum slidable in saidslot, a forked lower end for receiving a crank pin, and a lug near theupper end, a pair of spring strips mounted on said lug for straddlingthe two pins to urge them into alignment, the upper end of said leverbeing connected to a bomb sight actuated means to move said lever endsubstantially horizontally in a direction parallel to the valve shaft, afollow-up means connected to the rudder operating means, a crankoperated by said follow-up means having a crank pin, a second verticallydisposed lever having a fixed fulcrum and a crank pin at its lower endextending into the forked lower end of 9 the first vertically disposedlever, said second vertically disposed lever having a slot in its upperend for receiving the crank pin of the crank operated by the follow-upmeans, and means for manually adjusting the relation between said afollow-up means and the crank operated by said follow-up means.

4. In an aircraft automatic pilot having aileron iary rudder controlcomprising an auxiliary conoperating means and elevator operating meansinterconnected for operation in accordance with rudder movements and agyro controlled rudder operating means including a fluid motorcontrolled by a motive fluid control valve; an auxiliary rudder controlcomprising an auxiliary control valve having a horizontal axiallyslidable operating shaft, a longitudinal horizontally opening slot insaid shaft and a pin horizontally extending from said shaft adjacentsaid slot, a vertically disposed lever having a pin for a fulcrumslidable in said slot, a forked lower end for receiving a crank pin, anda lug near the upper end, a pair of spring strips mounted on said lugfor straddling the two pins to urge them into alignment, the upper endof said lever being connected to a bomb sight actuated means to movesaid lever end substantially horizontally in a direction parallel to thevalve shaft, a follow-up means connected to the rudder operating means,a crank operated by said follow-up means having a crank pin, a secondvertically disposed lever having a fixed fulcrum and a crank pin at itslower end extending into the forked lower end of the first verticallydisposed lever, said second vertically disposed lever having a slot inits upper end for receiving the crank pin of the crank operated by thefollow-up means, means for manually adjusting the relation between saidfollow-up means and the crank operated by said follow-up means, andmeans for selectively shifting the control of said rudder operatingmotor from one valve to the other whereby the aircraft may be controlledeither by the gyro or by the bomb sight.

5. In an aircraft automatic pilot having aileron operating means andelevator operating means interconnected for operation in accordance withrudder movements and a gyro controlled rudder operating means includinga fluid motor controlled by a motive fluid control valve; an auxiltrolvalve having a horizontal axially slidable operating shaft, alongitudinal horizontally opening slot in said shaft and a pinhorizontally extending from said shaft adjacent said slot, a verticallydisposed lever having a pin for a fulcrum slidable in said slot, aforked lower end for receiving a crank pin, and a lug near the upperend, a pair of spring strips mounted on said lu for straddling the twopins to urge them into alignment, theupper end of said lever beingconnected to a bomb sight actuated means to move said lever endsubstantially horizontally in a direction parallel to the valve shaft, afollow-up means connected to the rudder operating means, a crankoperated by said follow-up means having a crank pin, a second verticallydisposed lever having a fixed fulcrum and a crank pin at its lower endextending into the forked lower end of the first vertically disposedlever, said second vertically disposed lever having a slot in its upperend for receiving the crank pin of the crank operated by the follow-upmeans, means for manually adjusting the relation between said followupmeans and the crank operated by said followup means, means forselectively shifting the control of said rudder operating motor from onevalve to the other whereby the aircraft may be controlled either by thegyro or by the bomb sight, and means for rendering said automaticcontrols ineffective so that the aircraft may be manually controlled.

PLINY G. HOLT.

